Mother Nature backs away from El Nino

Surface temperatures in the Pacific Ocean are cooling down. Not a big deal for your crop potential in the Midwest, right?

Wrong.

This trend, seen developing over the last 4 weeks, signals a shift back away from the El Nino pattern, toward which the ENSO (El Nino Southern Oscillation index) was moving as it edged away from the La Nina pattern that was partially to blame for Mother Nature keeping the lid on rainfall during much of this year's growing season.

Now, that trend back toward a La Nina system -- which keeps surface temperatures cooler in the Pacific and warmer in the Atlantic -- could begin to quickly affect crop potential in South America and, if it doesn't change, may keep things dry in North America for a while.

This map shows the general cooling of surface temperatures in the Pacific Ocean and the warmer temperatures in the Atlantic, signs of a move away from El Nino, weather experts say (graphic courtesy NOAA).

"With all eyes on the crucial upcoming South America crops, questions are abuzz as to what implications this pattern shift may have on future weather there," says Carrie Silver with MDA EarthSat Weather. "Concerns are also centered on the impacts on Australia wheat as well as the potential replenishment of soil moisture in the U.S. following the extensive drought."

Though it certainly marks movement away from a known weather variable, this shift doesn't automatically foreshadow the drought's continuation into 2013, Silver says. It does, however, complicate the mix of potential weather outcomes in the next 12 months. "The fading El Nino will likely lead to less certainty and increased variability in the long-range outlooks for many areas including the U.S., South America and Australia," she says.

Adds MDA EarthSat Weather senior ag meteorologist Don Keeney: "It is true that we are seeing a fading El Niño, but this does not mean that we are automatically headed for La Niña. While the easing of El Niño makes the idea of drought-busting rains in the U.S. and ideal growing conditions in South America less certain, the current trend away from El Niño does imply that the tropical Pacific will have less influence on weather patterns in most areas."